1. Field of the Invention
This invention relates to credit card readers and, more particularly, to credit card readers having improved gimbal type mounting of the transducing head.
2. Brief Description of the Prior Art
Credit cards and banking cards are usually provided with a data carrying magnetic stripe in which the card information is magnetically recorded. Three types of card readers are in common use: a swipping reader, a dip reader and a transport reader. In a dip reader, the card is dipped into a slot, while in a transport reader, the card is pulled mechanically through a long slot. In all situations, it is desirable to have a good close contact between the magnetic head of the reader and the magnetic stripe carried by the card which requires that head be able to follow and adjust to the less than flat contours of the card which may be warped beyond the international standards for cards. It has been found that small changes in the distance between the magnetic head and the magnetic stripe result in large changes in the reading ability of the head. The data read from the stripe may therefore be inaccurate.
In order to avoid this problem, it is desirable to maintain the head perfectly parallel and in contact with the magnetic stripe and to push the head against the magnetic stripe with uniform pressure even when reading across the irregularities of a heavily contoured card.
Prior art magnetic card readers, such as those shown in Townsend U.S. Pat. No. 4,110,803, Chabrolle U.S. Pat. No. 4,628,386, Okuna U.S. Pat. No. 4,581,523, Briane et al U.S. Pat. No. 4,806,744 and Nakata U.S. Pat. No. 4,040,108 teach the use of springs to apply pressure to maintain contact between the head and the magnetic stripe on a card. However, in these devices structural inaccuracies may result in the head being out of parallel with the magnetic stripe on the card. Thus, the aforementioned small changes in the distance between the head and the stripe may still be present to produce reading errors.